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Blue overhauled the AC1 SL for 2012, and we were fearful that increased stiffness or weight savings would result in a less-pleasing ride. Adjustments to the carbon material and layup lightened the frame by 110 grams (a medium is now claimed at 1,040 grams). Blue also says the new, tapered head tube is 4 percent stiffer. The seat and down tubes are taller in order to increase their aerodynamic efficiency. The company also claims its bottom bracket remains one of the stiffest in the category. Like many aero bikes, the AC1 SL sounds like a jet engine winding up for takeoff when it&rsquo;s rolling, amplifying road noise with a whoosh&mdash;our own version of a sonic boom&mdash;that makes you feel fast. <br />
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Read our full <a href="http://www.bicycling.com/gearfinderproductdetail?gfid=13025">Blue AC1 SL review</a>.<br />
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With an $11,000 price tag, this bike is not for everyone. But the refined subtleties of Campagnolo&rsquo;s top-tier drivetrain mated with a bike Bianchi calls its &ldquo;highest performer ever&rdquo; is alluring. The Italian bike maker&rsquo;s hallmark Celeste paint is applied to a full-carbon monocoque frame with a diamond-shaped aero down tube, which feeds into a stiffness-enhancing BB30 bottom bracket. A wing-shaped fork crown, internal cable routing, and aero-shaped head tube and seatpost also boost efficiency. Component highlights include tubeless-compatible Fulcrum Racing Zero wheels and an FSA K-Force Compact Carbon bar. Frame sizes range from 47cm to 61cm. The claimed weight for a size 55cm is a feathery 970 grams. And the name? It means &ldquo;beyond&rdquo; in Italian, a reference to this bike&rsquo;s capabilities on the race course, or any ride.<br />

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If bikes were ranked based on their riders, the 2011 Canyon Aeroad CF would have few rivals. Under the guidance of Belgian superstar Philippe Gilbert, the Aeroad was first to finish at Amstel Gold, Fl&egrave;che Wallonne, Li&egrave;ge-Bastogne-Li&egrave;ge, and Stage 1 of the Tour de France. Gilbert has since switched teams and bikes, but the Aeroad remains a top-tier race machine, now available in seven configurations, including the new Katusha team bike. Designers increased aerodynamic efficiency by reducing the frame&rsquo;s frontal area, with an hourglass-shaped head tube and wing-shaped fork blades. The shorter fork and lower bearing seat also bring down the center of the head tube, resulting in a more aero rider position. The 9.0 Team model is equipped with a Shimano Di2 drivetrain, Mavic Cosmic Carbone SLR wheels, and Ritchey WCS carbon stem and bar.<br />

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A pioneer in the aero road-frame market, Cerv&eacute;lo crafted its first wind-cheating carbon-fiber bike 16 years ago&mdash;and its bikes have been a mainstay in the pro peloton. (The company is presently a partner with the Garmin-Barracuda squad.) Those pro riders will turn to the Cerv&eacute;lo S5 Team for regular competition use, but amateurs who actually have to pay for their bikes can reap many of the same rewards aboard the budget-friendly S2. Component highlights include an aero Cerv&eacute;lo SL seatpost, an FSA Omega compact bar, Fulcrum Racing T wheelset, and SRAM Rival shifters and derailleurs. The frame is constructed from custom-selected high-modulus carbon, and geometry is lowered to place the rider in a more aero position. Other highlights include an aero head tube and seatstays, ICS3 internal cable stops, oversize bottom bracket, and a 3T Funda Pro fork.<br />

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Since its debut at the 2008 Tour de France, Felt&rsquo;s AR line has gained a reputation for all-day comfort and aero efficiency. Stage 3 of the &rsquo;08 Tour provided one memorable moment: Will Frischkorn piloted his AR into a 200-kilometer breakaway, barely missing a heroic stage win. In fact, according to Felt, wind-tunnel testing revealed that riders on an AR1 can ride an hourlong course 58 to 75 seconds faster than on a bike with traditional tube shapes. This year, the bike serves as the primary weapon for the Argos-Shimano squad. Riders will benefit from the AR1&rsquo;s wind-tunnel-driven frame design, fabricated with UHC-Nano carbon fiber and equipped with Shimano Dura-Ace Di2. Internal cable routing and Felt&rsquo;s Aero Road UHC Ultimate monocoque fork further reduce drag. Spec highlights include the versatile Shimano WH-7900 35mm carbon clincher wheels. <br />

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After several years of problems with its distribution chain, Kuota is back in North America. That&rsquo;s good news for devotees of these stealthy, race machines. The Kult is the successor to the Kredo Ultra. The company says the bike is the &ldquo;perfect union between technology and aesthetics.&rdquo; To back up its claims, Kuota designed modified aero-frame shapes to enhance airflow around frame tubes, internal cable routing, and a beefed-up bottom bracket with a BB30 insert for increased stiffness and drivetrain rigidity. A dual-position, semi-integrated aero seatmast allows you to dial in your perfect position, but still gives you the performance of an integrated seatmast. For $6,000, you get a Shimano Dura-Ace drivetrain and American Classic Victory 30 wheels (not shown). You can upgrade to a Shimano Dura-Ace Di2 electronic drivetrain for an additional $2,650.<br />

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New for 2012, the sleek, race-ready Ci2 pairs Litespeed&rsquo;s top-end carbon aero frame with Shimano&rsquo;s new Ultegra Di2 electronic-shifting system. Other features include a ride-stiffening BB30 bottom bracket, a zero-stack headset for cleaner aerodynamics, and a 11/8- to-11/2-inch tapered steerer for increased front-end stiffness. The fork&rsquo;s bow shape lets more air pass smoothly between the legs and wheel. The frame itself is built of T40 nanotech carbon fiber, which Litespeed claims is lighter and stronger that the standard plies used in many bike frames. The company&rsquo;s boldest claim, though, is that the sum of all these aero enhancements is a 16-percent average in needed power output at all yaw angles when compared with nonaero bikes. That, as Litespeed notes, is like getting the benefit of pricey race wheels without having to pull out the credit card.<br />

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Instead of bladelike frame tubes, the Alize has squat shapes to carefully direct airflow. Also seen on bikes from other brands, this design takes a standard airfoil, like a wing, and truncates it at the tail, creating a stronger structure that still provides aero benefits. Named for a northeasterly trade wind, Alize was built for cyclists riding gran fondos&mdash;or anyone who regularly heads out for long rides. While the bike will certainly please many of those cyclists, racers will also enjoy it, thanks to its fast handling. The frame has an impressively unified, efficient feel, and there&rsquo;s just enough give to let you confidently rail high-speed corners. The ride is race-bike rumbly, especially through the rear end, which may turn off cyclists looking for protection from uneven pavement. <br />

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Belgian bike maker Ridley was the first manufacturer to score a 2012 WorldTour victory, with Lotto-Belisol rider Andre Greipel snagging the opening stage at January&rsquo;s Tour Down Under in Adelaide, Australia. He rode the wind-cheating FB Fast, which has aerodynamic enhancements Ridley calls FAST Concept, or Future Aero Speed Technology. Front and rear brakes are integrated parts of the frame and fork, rather than bolted-on components. A textured surface in strategic locations enhances airflow and reduce drag, and the fork is equipped with foils that draw air away from the spokes. The net effect, Ridley claims, is a bike that&rsquo;s nearly 2 miles per hour faster in sprints, and requires 20 fewer watts to maintain 25 mph in a breakaway. The frame is compatible with electronic drivetrains, and a PressFit 30 bottom bracket ensures that every pedal stroke is propelling you down the road.<br />

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Development on the Venge commenced in 2006. Specialized thought it had a viable design in &rsquo;09, only to be rebuffed by international racing regulations. Twenty-one trips to five wind tunnels later, the Venge was unveiled to much ballyhoo in 2011. Indeed, the new bike was fast, enough for sprinter Mark Cavendish to ride it to numerous WorldTour wins. A one-piece bottom bracket-chainstay increases pedaling efficiency. Internal cable routing and wispy Roval Rapide EL 45 wheels reduce drag. The semicompact 52/36 chainring paired with a SRAM 11-28 cassette engenders high-cadence spinning. Six sizes (49cm to 61cm) help riders find the right fit.<br />

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Even after a century in the business, Italian bike maker Wilier Triestina isn&rsquo;t opposed to seeking outside counsel. When the time came to enter the aero-bike fray, Wilier brought in renowned aerodynamics expert John Cobb to design a new, wind-slicing frame. The end result was the Imperiale, a Shimano Ultegra-equipped speedster with Fulcrum Racing 5 wheels; a Ritchey Pro bar, stem, and seatmast cap; and a Selle Italia SLR XP saddle. But it&rsquo;s Cobb&rsquo;s aero influence that defines this carbon monocoque frame. He claims that the leading edge on the &ldquo;splitter&rdquo; down tube cleans up (and speeds up) air coming off the spinning front wheel. The head tube is shaped to lift air away from the front wheel; the seat tube-seatstay cluster then moves air smoothly past the seat tube; and, finally, the seatstays are further shaped to guide air past the rear wheel.<br />